1. Field of the Invention
The present invention generally relates to a circuit board and a manufacturing method thereof, and more particularly, to a circuit board having a cavity and a manufacturing method thereof.
2. Description of Related Art
Today's market demands electronic products to be designed small, slim, light, and highly portable. Accordingly, the assembled thickness of electronic devices and a circuit board in such an electronic product has to be reduced too.
Conventionally, the assembled thickness of an electronic device (such as a chip packaging structure) and a circuit board is reduced by forming a cavity on the circuit board and disposing the electronic device in the cavity. FIG. 1 is a cross-sectional view of a conventional circuit board. Referring to FIG. 1, the circuit board 100 has a core layer 110 and circuit structures 120 and 130 respectively disposed on and below the core layer 110. The core layer 110 has a core dielectric layer 112 and two circuit layers 114 and 116 respectively disposed on and below the core dielectric layer 112. A cavity R1 runs through the circuit structure 120 and the core dielectric layer 112 and exposes the circuit layer 116.
In a conventional manufacturing process of the circuit board 100, additional layers are added to both sides of the core layer 110 to form the circuit structure 120 and the circuit structure 130, and a portion of the circuit structure 120 and a portion of the core dielectric layer 112 are removed to expose the circuit layer 116. Thus, the circuit layer 116 is embedded in a dielectric layer 132 of the circuit structure 130.